NOTE:Material in this section of the website is being
prepared based on the Draft Australian Physics Curriculum developed by ACARA (Australian Curriculum, Assessment and Reporting Authority).
The material itself and/or the arrangement of this material may change as
the Australian Physics Curriculum reaches implementation stage in 2012-2013.

This experiment asks students to use vernier calipers to
measure the dimensions of a cylinder and then to calculate the volume of the
cylinder. Students are asked to determine the absolute and relative errors
in the measured values and then to calculate the absolute error in the volume.
This experiment can also be used as an example of how to write Experiment
Reports in Physics.

Click on the following link to access a pdf file of the Experiment Report.
This file also contains explanatory notes & diagrams on vernier calipers.

This prac is very
simple but is required by the Syllabus.The
main point of this prac from my view is to introduce you to the linear air track
as a piece of physics equipment.We
will use the air track again (next time with data loggers) to perform a momentum
conservation experiment.

Aim:

To measure the average speed of an object.

Method:

1.Place a small car on the linear air track at the end near the air source
(vacuum cleaner).

2.Arrange a metre ruler on the side of the air track.

3.Turn the air supply on by pressing the switch on the side of the vacuum
cleaner.

4.Push the metal clip on the car gently against the metal clip at the end
of the air track until the black pen mark on the side of the air track is just
covered by the car.

5.Release the car and measure the time taken for the car to move 1 metre
down the air track.

6.Record this data in the Table below.

7.Repeat the experiment 4 more times.Calculate the average speed of the car for each trial.

Results:

Table: Average Speed of Car over distance of 1 metre

The vertical Force Board consists of pulleys onto
which various masses can be hung.The
acceleration due to gravity acting vertically downwards produces the weight
force of each set of masses.The
pattern of forces can then be traced onto paper (or photographed using a digital
camera) and the forces analysed using vector analysis.

Aim:

To demonstrate vector addition & subtraction.

Method:

1.Use the Force Board supplied to arrange an example of equilibrium of
forces.That is, arrange the
three sets of masses and mass carriers on the board so that there is no movement
 one set at each end of the string and one in the middle.Once there is no movement, the three weight force vectors are in
equilibrium.

2.Place a blank sheet of paper behind the middle mass carrier and carefully
trace the pattern made by the string and mass carrier so that your diagram
clearly shows the angles made by the string and the middle mass carrier.These are the same as the angles made between the three force vectors.

3.Determine the magnitude (size) of each force vector in newtons by using F
= ma, assuming a= 9.8 ms-2.Record these in the Table below.

4.Use your traced diagram and a protractor to measure the angles between
the force vectors.Record these in
the space provided over the page.

5.In the space provided below, use the information you have collected to
draw a scaled vector diagramshowing the addition of the three force
vectors.Since the forces are
in equilibrium, your diagram should form a closed vector polygon.In other words, your three vectors should add together to give zero
 the size of the net force acting on a system in equilibrium.

NOTE: If you need to review how to draw scaled vector
diagrams, check the notes provided on the Moving
Aboutmain page and especially Example
3.

Results:

Table: Size of Forces

Force
Number*

Total
Mass Hanging (kg)

Size of
Force (N)

1

2

3

*See diagram below for
numbering of forces.

Angle between Force 1 and 2 = ____________

Angle between Force 2 and 3 = ____________

Angle between Force 3 and 1 = ____________

Now draw your Scaled Vector
Addition Diagram:

Scale: ___________

Now draw a scaled vector diagram to calculate the
resultant vector of the subtraction Force 2  Force 1.Vector subtraction is covered on the Moving
About main page.

To investigate the relationship between the mass of a body
and the acceleration produced by constant force acting on that body.

Method:

1.Set up the experimental apparatus as shown below.

2.Measure the mass of the trolley car with string & interrupt card
attached.

3.Launch and set-up the Timing Software.

4.Choose a pulling force by placing four to six 50g masses on the mass
carrier provided.This pulling
force will remain the same throughout the experiment.

5.Hold the trolley car in the start position.Check that the string moves freely over the pulley with the weight
attached and that the trolley car will move in a straight path through the light
gate without colliding with anything.

6.Return the trolley car to the start position.Click on the Run icon to start the timing software and release the
trolley car.The acceleration
of the car will be measured as the interrupt card passes through the light gate
and should appear in the Table & graph on the computer screen.

7.Click on the Run icon to turn off the timing and move the car back
to the start position.

8.Add a 500g mass to the car.

9.Click on the Run icon to re-start the timing & release the
trolley.

10.Repeat steps 7 to 9 until the total mass added to the trolley is 2.0kg.

To investigate the relationship between the acceleration of
a system of constant mass and the applied net force acting on that system.

Method:

Use the same basic method as for the Prac No.3 but this
time start with five 50g masses on the trolley and a 50g mass carrier hanging
over the pulley to act as the initial force on the system.Measure the acceleration produced.Increase the force on the system by transferring one 50g mass
from the trolley to the mass carrier and repeat the experiment.Note that the total mass of the system remains constant as you increase
the force acting on the system.Continue
until all of the 50g masses are on the mass carrier.(Note: By system in this prac, we mean the trolley + masses on
trolley + interrupt card + masses hanging over pulley + cord.The force due to gravity acting on the masses hanging over pulley is
applied to this whole system NOT just to the trolley.)

If you wish to take the prac
further, you can calculate the mass of the whole system from the slope of the
acceleration v's force graph and then compare this mass with the value obtained
using electronic scales.Mass of
system = 1/slope of your graph.

Practical No. 5  Acceleration
Due to Gravity By Ticker-Timer

Introduction:

The Ticker-Timer
provides a simple means of collecting distance versus time data in motion
experiments.Today it has been
superseded by the data logger.It
is, however, worthwhile to have a familiarity with data collection using the
Ticker-Timer. Teachers should discuss with
students the relative merits of the two instruments.

Aim:

To determine the local value of the acceleration due to
gravity using the ticker-timer.

Method:

1.Set up the equipment as shown below.

2.Turn power on and drop paper tape, allowing the attached weight to pull
it through the ticker-timer.

3.Examine tape to ensure that the dots are spaced so as to indicate
uniformly accelerated motion.If
not, repeat step 2.Do not waste
tape!

4.Produce a tape that has at least six dots in a row from the start clearly
showing uniformly accelerated motion.Analyse this section of the tape to complete the Table below.Take more dots into account if you can.Remember that the time between consecutive dots is 0.02 seconds (1/50
s  the frequency of the mains supply).

5.Draw a graph of average velocity versus time and calculate the slope
of this graph.Remember that
average velocity over a time interval occurs at the middle of that time
interval.The value of the slope is
your experimental value of the local acceleration due to gravity.

Results:

Table: Analysis of data from tape

Interval
No.

Time for
each Interval (s)

Displacement
covered in each Interval (cm)

Average
Velocity during each Interval (cm/s)

Total
time elapsed to middle of Interval (s)

1

0.02

0.01

2

0.02

0.03

3

0.02

0.05

4

0.02

0.07

5

0.02

0.09

Draw your graph of Average
Velocity versus Time.

Slope of your average velocity versus time graph =
__________

Comment on any discrepancy between your experimental
value of the acceleration due to gravity and the accepted average value of 980
cms-2.

Practical No. 6  Balls on
Slopes

Introduction:

In a now famous
experiment, Galileo demonstrated that the motion of a ball rolling down an
inclined plane is uniformly accelerated motion.From this he extrapolated
that the motion of any body free falling vertically is also uniformly
accelerated motion.

Using the principle of
conservation of energy and some basic rotational kinematics, it can be shown
that for a solid spherical ball rolling down an inclined plane, the linear speed
of the ball at the bottom of the inclined plane is given by:

where v
= linear speed of ball at bottom of incline, h
= height of inclined plane and g
= acceleration due to gravity, which can be assumed to be 9.8
ms-2.

Aim:

To verify that the speed of the ball at the bottom of the
inclined plane is proportional to the square root of the height of the incline.

Your Task:

Design a Method for achieving the above Aim.HINTS: Remember your basic definitional equations
for average velocity given earlier in this course.Remember the benefit of graphs and straight-line relationships between
variables.Use the equipment
available to check out the practicality of your ideas.

Practical No. 7 
Conservation of Momentum

If no external net force acts during a
collision, the total momentum of the system is not changed by the collision and
therefore the total momentum of the system before collision equals the total
momentum of the system after collision.
The practical that follows is based on Experiment M15 Inelastic
Collisions from the Sensing Science software from Data Harvest.

Aim:

To analyse the change in momentum of a system of two linear
air track vehicles during collision.

Method:

1.Set up the equipment as shown in the following diagram.
The light gates are connected to the input terminals of a data logger as
shown. Place blue tack firmly on the ends of vehicles 1 & 2 that are facing
each other.Measure and record the
masses of vehicles 1 & 2 with blue tack & interrupt cards attached.
Note that the diagram below was copied from the notes supplied with Experiment
M15 Inelastic Collisions from the Sensing Science software from Data Harvest.
Note also that the pin & cork shown on the ends of the vehicles were
replaced by blue tack in our version of the practical.

2.Launch and set-up the Timing Software to enable the velocity of vehicle 1
to be measured before the collision and the velocity of vehicle 1 & 2
combined to be measured after collision.

3.Click on the Run icon to start the timing software.The relevant velocities will be measured as the interrupt cards pass
through the relevant light gates and should appear in the Table & graph on
the computer screen.

4.Turn the air on in the linear air track.Hold vehicle 2 at rest in a designated spot between the light gates until
vehicle 1 is in motion.

5.Push the metal clip on vehicle 1 firmly against the metal clip at the end
of the air track until the black pen mark on the side of the air track is just
covered by vehicle 1.This will
allow vehicle 1 to spring forward when released. The clips & pen mark
are not shown in the diagram above. There are many ways of applying an
initial force to vehicle 1 in a consistent manner.

6.Release vehicle 1 and record the velocities measured by the data logger
in the Table below.Record the
before and after velocities only for cases where the vehicles collide and
coalesce.

7.Repeat the experiment 4 more times.

Results:

Table No.1: System Data Before Collision

Trial No.

Mass of
Vehicle 1 (kg)

Velocity of
Vehicle 1 (m/s)

Mass of
Vehicle 2 (kg)

Velocity of
Vehicle 2 (m/s)

Total
Momentum of System Before Collision (Ns)

1

0

2

0

3

0

4

0

5

0

Table No.2: System Data After Collision

Trial No.

Mass of Vehicles 1 & 2 Combined (kg)

Velocity of Combined Vehicles (m/s)

Total
Momentum of System After Collision (Ns)

1

2

3

4

5

Table No.3: Change of Momentum of System During Collision

Trial No.

Change of Momentum of System During Collision (Ns)

1

2

3

4

5

Conclusion:

Comment on the extent to which your results support the
idea that if no external net force acts during a collision, the total momentum
of the system is not changed by the collision.